Test Kitchen video tip: Making meringue

Essentially a combination of egg whites and sugar whipped to frothy peaks, meringue is a simple but key player in a variety of baking and pastry recipes.

Use it as a topping, gracing lemon or key lime pies, or maybe spread it over a cake as a classic seven-minute frosting. It can be used as a leavener, added to cake batters (angel food, chiffon and other sponge cakes) to lighten the crumb, give lift to souffles, or used to lighten custard and cream fillings. Bake it as a dessert element (a vacherin or hard meringue container) or use it as the base for macaron cookies. The options are almost endless.

To make the most of your meringue, follow a few basic tips:

Use room temperature egg whites. Room temperature egg whites will give greater volume than cold whites just out of the refrigerator.

Whip the whites using a clean bowl and beater. Dirt and oils will prevent the whites from properly foaming as they are beaten.

Sometimes acids (lemon juice, cream of tartar) are added to the whites. Acids help the whites to foam and make them stable.

Beat the whites over low speed to strengthen the structure of the bubbles as they form, then slowly "rain" in the sugar with the mixer going, a tablespoon or so at a time. If incorporating cooked sugar, with the mixer running, slowly pour the sugar off to the side away from the beater to keep it from hitting the beater and splashing on the sides of the bowl. (Sugar hitting the sides of the bowl can cool and harden quickly; if this happens, don't try to incorporate it into the meringue -- it won't incorporate, and will only make the meringue lumpy.)

Keep beating (you can slowly increase the speed of the mixer), just until the whites come to the correct volume, whether soft (peaks fall over when beater is lifted), medium (peaks droop slightly) or stiff (shown at top -- peaks stay firm) peaks.

Be careful not to overbeat the eggs. Check the eggs periodically as they thicken; if the eggs overbeat (they will look crumbly), their delicate structure will break down. The meringue should look smooth, shiny and moist; overbeaten meringues cannot be fixed.

If you have any kitchen tips or questions you'd like me to explore, leave a comment below or shoot me an email at noelle.carter@latimes.com.

Graham cracker crumb crust

2. To make the crust by hand, place the crackers in a freezer bag and use a rolling pin to crush them into fine crumbs. In a medium bowl, combine the crumbs and sugar and toss with a fork to blend. Stir in the melted butter and toss to incorporate it. To make the crust using a food processor, process the crackers with the sugar until the crackers become fine crumbs, about 20 seconds. Add the melted butter and pulse just until incorporated, about 10 times.

3. Using your fingers or the back of a spoon, press the mixture into the bottom of the pie pan and partway up the sides. To keep the crumbs from sticking to your fingers, it helps to place a piece of plastic wrap over the crumbs and press them through the wrap. Then switch to a flat-bottomed, straight-sided measuring cup or glass to smooth the crumbs over the bottom and all the way up the sides. Be sure to press the bottom thoroughly so that the crumbs are evenly distributed. Place the crust in the oven and bake just to set the crust (the crust will color just slightly), about 6 minutes.

Filling and assembly

4 eggs (at room temperature), separated and divided

1 1/4 cups (one 14-ounce can) sweetened condensed milk

1 1/2 teaspoons finely grated Key lime zest

3/4 cup fresh Key lime juice

1/2 cup sugar, preferably superfine

2 tablespoons water

1/2 teaspoon cream of tartar

1 tablespoon powdered sugar (optional)

1. In a medium mixing bowl, lightly whisk the egg yolks with the sweetened condensed milk. Gradually beat in the lime juice. (It will cause the mixture to thicken.) Beat in the zest and set aside.

2. In the bowl of a stand mixer, or in a large mixing bowl with an electric mixer, beat the egg whites until foamy. Add the cream of tartar and beat until stiff peaks form when the beater is raised slowly. Set aside.

3. In a small, heavy saucepan, stir together the sugar and water until the sugar is completely moistened. Heat, stirring occasionally, until the sugar dissolves and the syrup begins to bubble. Stop stirring and reduce the heat to a gentle simmer and continue cooking until a thermometer inserted reads 236 degrees (soft ball stage). Immediately remove from the heat.